Problem: Christopher has driven his car for a total of $20$ miles since he started driving daily. He has been driving $4$ miles each day. For how many days has Christopher been driving?
The number of days that Christopher has been driving is the total number of miles driven divided by the number of miles driven each day. $20\text{ miles} \div 4\text{ miles per day} = \text{number of days driving}$ $20\text{ miles} \div 4\text{ miles per day} = 5\text{ days}$